Examples of RAIDs
Consecutive blocks (say, sectors) 0,1,2,… spread over different disks
RAID 0 has no redundancy, so it is not a real RAID.
It does not improve availability while worsens reliability.
But it does improve throughput up to 4 times for large-block requests.
RAID 1 uses mirroring (full duplication), so availability is excellent.
Also, reads can be up to 2 times faster than in RAID 0.
Some more space-efficient RAIDs use parity rather than mirroring.